An alternate tool for identifying large-scale structures is Fourier analysis [1]}, which is relatively easier to compute. Recently, Chandra and Verma [2]} showed that the Fourier modes play a critical role in the reversal dynamics of turbulent convection. Note that a large number of low-dimensional models have been constructed using the large-scale Fourier modes. There are several low-dimensional models based on POD modes as well [3]}, [4]}, but Fourier modes are more amenable for this purpose.
